Growth of free-standing bulk wurtzite AlxGa1−xN layers by molecular beam epitaxy using a highly efficient RF plasma source

Novikov, Sergei V.; Staddon, Christopher R.; Sahonta, S-L; Oliver, R.A.; Humphreys, C.J.; Foxon, C.T.

Abstract

The recent development of group III nitrides allows researchers world-wide to consider AlGaN based light emitting diodes as a possible new alternative deep ultra–violet light source for surface decontamination and water purification. In this paper we will describe our recent results on plasma-assisted molecular beam epitaxy (PA-MBE) growth of free-standing wurtzite AlxGa1−xN bulk crystals using the latest model of Riber's highly efficient nitrogen RF plasma source. We have achieved AlGaN growth rates up to 3 µm/h. Wurtzite AlxGa1−xN layers with thicknesses up to 100 μm were successfully grown by PA-MBE on 2-inch and 3-inch GaAs (111)B substrates. After growth the GaAs was subsequently removed using a chemical etch to achieve free-standing AlxGa1−xN wafers. Free-standing bulk AlxGa1−xN wafers with thicknesses in the range 30–100 μm may be used as substrates for further growth of AlxGa1−xN-based structures and devices. High Resolution Scanning Transmission Electron Microscopy (HR-STEM) and Convergent Beam Electron Diffraction (CBED) were employed for detailed structural analysis of AlGaN/GaAs (111)B interface and allowed us to determine the N-polarity of AlGaN layers grown on GaAs (111)B substrates. The novel, high efficiency RF plasma source allowed us to achieve free-standing AlxGa1−xN layers in a single day's growth, making this a commercially viable process.

Citation

Novikov, S. V., Staddon, C. R., Sahonta, S.-L., Oliver, R., Humphreys, C., & Foxon, C. (in press). Growth of free-standing bulk wurtzite AlxGa1−xN layers by molecular beam epitaxy using a highly efficient RF plasma source. Journal of Crystal Growth, https://doi.org/10.1016/j.jcrysgro.2016.07.038

• Journal Article Type: Article
• Acceptance Date: Jul 26, 2016
• Online Publication Date: Jul 27, 2016
• Deposit Date: Aug 5, 2016
• Publicly Available Date: Aug 5, 2016
• Journal: Journal of Crystal Growth
• Print ISSN: 0022-0248
• Electronic ISSN: 0022-0248
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1016/j.jcrysgro.2016.07.038
• Keywords: A1. Substrates; A3. Molecular beam epitaxy; B1. Nitrides; B2. Semiconducting III–V materials
• Public URL: https://nottingham-repository.worktribe.com/output/799261
• Publisher URL: http://dx.doi.org/10.1016/j.jcrysgro.2016.07.038
• Contract Date: Aug 5, 2016